Semiconductor devices, such as transistor devices, may be used for various applications, such as switches in power supplies and power converters. Examples of transistor devices include a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) and an Insulated Gate Bipolar Transistor (IGBT). It is desirable that the semiconductor devices, in particular transistor devices, have a good and reliable performance. The performance of power MOSFETs is influenced by static and dynamic losses among other factors. Static losses occur due to various contributors to on resistance (RDSon), drain source leakage current (IDSS), gate source leakage current (IGSS) and forward voltage. Dynamic losses occur mainly due to input and output capacitance and gate resistance.
Some MOSFET devices include a compensation structure to reduce the on-state resistance of the semiconductor device and improve performance. The compensation structure may include a vertical field plate arranged within a trench extending into the semiconductor body of the transistor device. The transistor device may include a vertical gate, which may be arranged in the trench above and isolated from the vertical field plate or in a trench that is separate from the trench including the field plate, or the transistor device may include a planar or lateral gate which extends substantially perpendicularly to the vertical field plate.
Transistor structures, which enable reliable performance of the transistor device, are desirable.